Atmospheric Neutrinos

The results of experiments on atmospheric neutrinos are summarized, with the important exception of Superkamiokande. The main emphasis is given to the Soudan-2 and MACRO experiments. Both experiments observe atmospheric neutrino anomalies in agreement with nu_mu-->> nu_tau oscillations with maximum mixing. The nu_mu-->> nu_sterile oscillation is disfavored by the MACRO experiment.Comment: To be published in the proceedings of TAUP99 Conference College de France - Paris 6-10 September 1999 11 pages 12 figure

Towards Precision Muonic X-Ray Measurements of Charge Radii of Light Nuclei

Precision studies of the properties of nuclei are essential both for understanding nuclear physics at low energy, and for confronting experiment and theory in simple atomic systems. Such comparisons advance our understanding of bound-state quantum electrodynamics and are useful for searching for new physics beyond the Standard Model. The energy levels of muonic atoms are highly susceptible to nuclear structure, especially to the RMS charge radius. The radii of the lightest nuclei ($Z=1,2$) have been determined with high accuracy via laser spectroscopy in muonic atoms, while those of medium mass and above, from X-ray spectroscopy with semiconductor detectors. In this communication we present a new experiment aiming at precision measurements of the radii of light nuclei $3 \leq Z \leq 10$ via single-photon energy measurements with cryogenic microcalorimeters; a quantum sensing technology capable of high efficiency and outstanding resolution for low-energy X-rays

Towards Precision Muonic X-ray Measurements of Charge Radii of Light Nuclei

Funding Information: B.O. is thankful for the support of the Council for Higher Education Program for Hiring Outstanding Faculty Members in Quantum Science and Technology. The Kirchhoff Institute for Physics group at Heidelberg University is supported by Field Of Focus II initiative at Heidelberg University. D.U. acknowledges the support by the Research Training Group HighRR (GRK 2058) funded through the Deutsche Forschungsgemeinschaft, DFG. The work of the KU Leuven group is supported by FWO-Vlaanderen (Belgium), KU Leuven BOF C14/22/104, and European Research Council, grant no. 101088504 (NSHAPE). P.N. acknowledges support from the NSERC Grant No. SAPIN-2022-00019. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. The Lisboa group is supported in part by Fundação para a Ciência e Tecnologia (FCT; Portugal) through research center Grant No. UID/FIS/04559/2020 to LIBPhys-UNL. The work of the ETH group was supported by the ETH Research Grant 22-2 ETH-023, Switzerland. Publisher Copyright: © 2024 by the authors.We, the QUARTET Collaboration, propose an experiment to measure the nuclear charge radii of light elements with up to 20 times higher accuracy. These are essential both for understanding nuclear physics at low energies, and for experimental and theoretical applications in simple atomic systems. Such comparisons advance the understanding of bound-state quantum electrodynamics and are useful for searching for new physics beyond the Standard Model. The energy levels of muonic atoms are highly susceptible to nuclear structure, especially to the mean square charge radius. The radii of the lightest nuclei (with the atomic number, (Formula presented.)) have been determined with high accuracy using laser spectroscopy in muonic atoms, while those of medium mass and above were determined using X-ray spectroscopy with semiconductor detectors. In this communication, we present a new experiment, aiming to obtain precision measurements of the radii of light nuclei (Formula presented.) using single-photon energy measurements with cryogenic microcalorimeters; a quantum-sensing technology capable of high efficiency with outstanding resolution for low-energy X-rays.publishersversionpublishe

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Mass separation of 225Ac for medical applications: first proof of principle at CERN-MEDICIS

Due to its promise as a medical radioisotope, global demand for 225Ac is beyond the current possible production rate. Several new techniques have already been proposed to increase the production, but further research is required. For its use in treatment, other isotopes, that could potentially be harmful, have to be removed. This purification can be achieved with several methods, but the most promising are chemical separation and mass separation. While the former generally has a higher efficiency, the latter is known for the high isotopic purity that can be achieved with it. Within the scope of this general research lies MED-024, which is an experimental campaign that is investigating the production and mass-separation of 225Ac. In this thesis, the focus will be on characterising the ISOL process efficiency of two specific collections. Both of these used a nitrate solution of 225Ac, with known activity, obtained from the Joint Research center (JRC) in Karlsruhe (Germany). The first run dried the solution on a rhenium foil directly. On the other hand, the second evaporated the 225Ac on a thorium-dioxide felt, where it was assumed that the 225Ac would be distributed homogeneously throughout the porous target material, though without penetrating the target grains. These runs mainly concentrate on the ionization and separation efficiency of 225Ac offered by the laser ionization setup at CERN-MEDICIS. Zinc-coated gold foils were implanted with mass-separated 225Ac and sent to IKS for a detailed activity analysis. Three different techniques were used to measure the activity at different times, which enabled the end of collection activity to be determined by extrapolation. These methods were single g-ray spectroscopy, g-g coincidence measurements and a-spectroscopy. Each of these has its own advantages and disadvantages. For the a-spectroscopy, more accurate geometric efficiency calculations were required. For this, three models were created. The first of these is a semi-analytical method, in which the source distribution is assumed. Once the geometric efficiency is put in terms of an integral that can not be solved analytically, numerical Monte Carlo techniques were used. The other two models (NRAM and FNM) started from a more numerical basis. SRIM was used to model the stopping and redirection of a-particles and recoiling daughter nuclei within and out of the sample. The NRAM uses extrapolation of the particle trajectories in combination with assumptions on probabilities of physical processes once the particles leave the sample. The FNM, on the other hand, models the entire source-detector geometry directly. The resulting collection efficiencies were equal to 9.77(19)%for the first collection and 8.99(48) % for the second. These are only lower bounds to the best achievable efficiency, as the optimization of the setup was performed during the collection and the samples were temporarily removed for mass scans. Furthermore, the second collection had to be ended before saturation was reached. The results from the second run indicate that the effusion efficiency is negligible

Blockchain-driven supply chain finance: Towards a conceptual framework from a buyer perspective: Presentation held at 26th Annual IPSERA Conference 2017, 09-12 April 2017, Budapest

The main objective of this article is to develop a conceptual framework for blockchain-driven supply chain finance (SCF) solutions. The frame of reference intends to foster the coordination in buyer-supplier relations and eliminates existing inefficiencies in the execution of discrete SCF-instruments, such as reverse factoring and dynamic discounting. Moreover, we introduce value drivers for blockchain technology (BCT) to elaborate unique characteristics for its application in the field of SCF. While BCT is considered as one of the most disruptive enablers in financial technology (FinTech), it received only little attention within the emerging field of SCF. Therefore, the results contribute to future developments of appropriate SCF-solutions based on the newest technology innovations

Reconditioning of the Leuven Isotope Separator as a test bench for radioactive ion beam development

Producing novel medical radionuclides in the quantities necessary for pre-clinical and clinical use requires an ion source able to handle high ion throughputs, operated efficiently, to deliver high specific activity samples. This is only possible with the understanding of how different parameters affect the ion source performance. Offline mass separators are needed to run systematic studies that would help us to derive the laws governing those ion sources. At KU Leuven, we are refurbishing the Leuven Isotope Separator, a mass separator previously used for implantations of radioisotopes in solid-state samples and Mössbauer spectroscopy. In the past couple of years, the machine has undergone significant updates and has been adapted to integrate the target ion source units used at CERN-ISOLDE. This paper discusses the modifications to the Leuven Isotope Separator, as well as its potential as a test bench for the study of radioactive ion beams in the future

Resonant laser ionization and mass separation of 225^{225}Ac

$^{225}$Ac is a radio-isotope that can be linked to biological vector molecules to treat certain distributed cancers using targeted alpha therapy. However, developing $^{225}$Ac-labelled radiopharmaceuticals remains a challenge due to the supply shortage of pure $^{225}$Ac itself. Several techniques to obtain pure $^{225}$Ac are being investigated, amongst which is the high-energy proton spallation of thorium or uranium combined with resonant laser ionization and mass separation. As a proof-of-principle, we perform off-line resonant ionization mass spectrometry on two samples of $^{225}$Ac, each with a known activity, in different chemical environments. We report overall operational collection efficiencies of 10.1(2)% and 9.9(8)% for the cases in which the $^{225}$Ac was deposited on a rhenium surface and a ThO$_{2}$ mimic target matrix respectively. The bottleneck of the technique was the laser ionization efficiency, which was deduced to be 15.1(6)%

Muonic x-ray spectroscopy on implanted targets

Muonic x-ray spectroscopy uses muons to obtain information about the structure of the atom and the nucleus. In muonic atoms, the energy levels of atomic orbitals are significantly more sensitive to the finite size correction. By probing these orbitals using x-ray spectroscopy, the nuclear size correction can be extracted, providing valuable input for laser spectroscopy in the form of absolute charge radii with a relative precision better than 10−3. Continuing on developments that allowed measurements on target quantities of about 5 μg, we showed the feasibility of using implanted targets. In the future, this will allow the measurement of absolute charge radii of long-lived radioactive isotopes that are not available in sufficient enrichment or large quantities. In this contribution, we shall report on the target preparation, involving high-fluence implantation, and on the preliminary results of the muX experimental campaign.ISSN:0168-583XISSN:1872-958